Autoimmune pancreatitis in an 11-year-old boy.

We report a case of histopathologically proven autoimmune pancreatitis in an 11-year-old boy. Abdominal US and MRI showed a focal swelling of the pancreatic head, the latter also showing delayed contrast enhancement. There was diffuse irregular pancreatic duct narrowing, compression of the intrapancreatic common bile duct, and mild proximal biliary dilatation on MR cholangiopancreatography. Laboratory results revealed normal serum IgG and subclass 4 with negative autoimmune antibodies, and slightly elevated carbohydrate antigen 19-9. This highlights the differentiation of autoimmune pancreatitis from pancreatic head cancer and, to a lesser extent, other forms of pancreatitis in children.